121 is big enough to assume normality and not worry about the t distribution. By the 68-95-99.7 rule a 95% confidence interval includes plus or minus two standard deviations. So 95% of the cars will be in the mph range

The question is a bit vague, but it seems we're being asked for the 95% confidence interval on the average of 121 cars. The 121 is a hint of course.
The standard deviation of the average is in general the standard deviation of the individual samples divided by the square root of n:

So repeating our experiment of taking the average 121 cars over and over, we expect 95% of the averages to be in the mph range

That's probably the answer they're looking for.
Answer:
2400 words
Step-by-step explanation:
80 = 2 min
60min ÷ 2min = 30min
30 × 80 = 2400 words
<span>46, 37, 16, 24, 47, 23, 19, 31, 25
put in order</span>
16, 19, 23, 24, 25, 31,37, 46, 47
mean = 25
LOWER QUARTILE = (16+ 19+ 23+ 24) / 4 = 20.5
answer
Lower IQR = 20.5
Answer:
45.3 times 4 equals 181.2
Step-by-step explanation: